1. Field
Apparatuses and methods consistent with exemplary embodiments relate to capturing a magnetic resonance (MR) image, by which dense data may be obtained at a center of a k-space.
2. Description of the Related Art
Magnetic resonance imaging (MRI) forms an image based on information obtained by resonance after exposure of an atomic nucleus to a magnetic field. Resonance of the atomic nucleus is a phenomenon in which if a particular high frequency energy is incident into the atomic nucleus magnetized by an external magnetic field, the atomic nucleus in a low-energy state absorbs the high-frequency energy and thus is excited to a high-energy state. The atomic nucleus has different resonance frequencies according to its type, and resonance is affected by the strength of the external magnetic field. In the human body, numerous atomic nuclei exist and generally, a hydrogen atomic nucleus is used to capture an MR image of a patient.
An MRI system is non-invasive, has superior tissue contrast as compared to a computed tomography (CT), and generates no artifact due to a bone tissue. Moreover, the MRI system may capture various cross-sections in a desired direction without changing a position of an object, and thus has been widely used together with other image diagnostic apparatuses.
A diagnostic method based on MRI has various advantages, but when an MRI is performed, for example, to image a brain, a motion artifact generated by movement of an object may cause degradation of the quality of the MR image.
One approach to avoid the motion artifact is to eliminate an object motion. However, it is difficult to remove a cause for every motion artifact, as for example, breathing of a patient. When a high resolution image is required, such as for example, when imaging a brain, the motion artifact has a great influence upon the quality of the image, and statically, 40% of the MR images of the brain have motion artifacts, and 10% out of them need a rescan due to the motion artifacts.
Another approach is obtaining a large amount of effective captured data to improve a signal-to-noise ratio (SNR), or shortening a scan time. However, these two factors have a trade-off relationship, and therefore, a compromise for satisfying both of them at the same time is required. The scan time is directly proportional to the number of repetition times (TR), each of which refers to one period from a 90° pulse to the next 90° pulse in a pulse sequence, and its own length of TR.